Develop new or perfect existing methodologies for the separation, identification and quantitation of the major forms of retinoids and important carotenoids in foods. Appropriate standard reference materials and/or quality control samples need to be secured or developed for data validation. Efficient extraction procedures of retinoids and carotenoid from different food matrices need to be utilized which preserve the stable/unstable species and remove interfering compounds. Strategies to select important food items in the food supply and secure a representative sample of these items shall be developed. Important food items include those which contribute a major portion of retinoids and carotenoids in the U.S. food supply. By using this type of statistical sampling it is estimated that between 1500 and 2000 samples need to be analyzed. Additionally, data on the effects of processing on the above nutrients shall be collected. The procurement is expected to result in a reliable data base of retinoids and carotenoids in foods to be used in dietary assessment and prevention studies of NCI.